The present invention relates to a measurement tool or treatment tool for an endoscope.
A measurement tool for an endoscope is typically used for measuring a size of an ulcer or the like on a mucous membrane in a human cavity. The measurement tool is generally configured such that graduations are formed at a tip end portion of a flexible shaft, which is detachably inserted through an instrument tool insertion channel of the endoscope. An example of such a measurement tool is disclosed in Japanese Utility Model Publication HEI 6-44401.
With the measurement tool configured as described above, a size only in one direction can be measured, and a length in another direction cannot be measured. In order to measure the size of an object in two different direction, a direction where the graduations are provided should be changed. However, at the tip of the endoscope, at which a positional relationship with respect to the ulcer is limited, it is difficult to change the orientation of the distal end of the endoscope. Thus, it is almost impossible to directly measure the length of the object (e.g., ulcer) in two different directions. Therefore, a length in one direction should be guessed based on the measured length.
The Japanese Utility Model Publication HEI 6-44401 teaches a measurement tool provided with a flexible tube having two slits, which traverse the flexible tube in the diameter direction, at a certain interval along the axis of the flexible tube. By operation an operation wire, the distal end portion of the flexible tube, on which gradations are formed, is bent to form a T-shape. However, in such a configuration, the flexible tube is bent by 180 degrees at one of the two slits. Therefore, when such a bending operation is repeated, the flexible tube may be broken, at the slit, within a relatively short period of time.
Another typical tool for an endoscope is an injection tube for injecting contrast medium. A conventional injection tube is typically formed as a single tube made of flexible resin such as tetrafluoroethylene. An injection mouth is provided at the proximal end of the injection tube. At the distal end thereof, an end tip may be secured. In some injection tubes, a core metal is inserted so that the tube is not folded.
The tubular tool as described above is inserted in a treatment tool channel of an endoscope. In the conventional treatment tool, an orientation or a direction of a distal end portion of the tubular tool, which is protruded from the distal end of the endoscope, cannot be controlled. Therefore, according to the conventional art, the distal end portion of the flexible tube is formed to have tendency to bend in a predetermined direction. Even with such a tubular tool, it is still difficult to insert the tubular tool in a diverging tube at a deep portion of a bile duct or bronchial tubes.
Another typical treatment tool for an endoscope is a bendable treatment tool used for collecting tissues from a mucous membrane inside a human cavity.
As such treatment tools for collecting human tissues, ones having a brush tool or spoon tool are secured onto a tip end of a flexibly bendable sheath. An example of such a tool is described in Japanese Patent Provisional Publication HEI 05-142.
Conventional tools for collecting human tissues, as described in the above-described publication, are configured as precision instrument such that link members rotatable at respective rotation axes, which are perpendicular to the axis of the flexible tube, are provided at the tip end portion of the flexible sheath. The link members are configured to be bent/expanded upon back/forth movement of an operation wire.
With this precise structure, it is difficult to clean the tool completely after operation thereof. Further, due to the precise structure, the tool easily malfunctions. Due to the precise structure, such tools are relatively expensive and may not be disposable. Accordingly, the conventional tools may be reused in unstable condition.
Another typical treatment tool for an endoscope is a catheter, which is inserted in the forceps channel of an endoscope, and is used for feeding of chemicals or suction of bodily fluids.
The catheter for an endoscope is generally formed of a flexible tube having a simple structure. In order to lead the distal end of the catheter to a target position, it is preferable that the direction of the distal end portion is remotely changeable.
FIG. 35 shows a structure of a conventional catheter for an endoscope. As shown in FIG. 35, the conventional catheter includes a flexible tube 501. Inside the flexible tube 501, an operation wire 502 is loosely inserted. At the distal end portion of the flexible tube 1, a pair of holes 503 are formed, which are spaced along the axial direction by a predetermined amount. Between the holes 503, the operation wire 502 is located outside the flexible tube 501 and extends along the axis of the flexible tube 501. Further, the flexible tube 1 is provided with a plurality of circumferential grooves 504 at a predetermined interval so that the flexible tube 1 is easily bent.
In the catheter configured as described above, if the operation wire 502 has tendency to bend in a certain direction, the flexible tube 1 may meander. In such a case, the catheter cannot be used. Therefore, generally twisted wires having less rigidity are used as the operation wire 502.
When the operation wire 2 is pulled, the distal end portion of the flexible tube 501 is bent as indicated by two-dotted lines in FIG. 35. However, even if the operation wire is pushed, due to its low rigidity, the distal end portion of the flexible tube 1 may not bend. Thus, according to the conventional structure, it is very difficult to lead the distal end of the catheter to a desired direction.
A cytodiagnosis brush is known as treatment tool for an endoscope. Generally, the cytodiagnosis brush is configured such that a brush shaft provided with radially planted brush at the distal end portion thereof is connected with the distal end of a closely wounded coil pipe, which can be inserted in the treatment tool insertion channel of the endoscope.
Endoscopes should be cleaned and disinfected completely after they are used. However, for the cytodiagnosis brush described above, it is difficult to completely clean and disinfect inside the coil pipe. Therefore, in order to avoid contagion between patients via the cytodiagnosis brush, it must be disposed when it is used once, which has been considered wasteful.
Another typical treatment tool for an endoscope is a biopsy forceps for collecting biopsy tissues from the human cavity.
The biopsy forceps is generally configured such that an operation wire is movably inserted in a flexible sheath, and by moving the operation wire, a pair of forceps cups provided at the distal end of the flexible sheath are opened/closed.
In a conventional biopsy forceps configured as above, the direction of the distal end portion of the sheath cannot be changed. FIG. 46 schematically shows a branched portion of a brachial tube, in which an endoscope 750 is inserted. In FIG. 46, 701 denotes a flexible sheath and 702 denotes forceps cups. In this example, the endoscope should be inserted to a branched tube having a tumor 100. However, since the direction of the distal end portion of the flexible sheath 701 cannot be changed, when the flexible sheath 701 is protruded from the distal end of the endoscope, the flexible sheath enters the other tube as shown in FIG. 47.
Even if the flexible sheath 701 can be introduced in the desired tube, as shown in FIG. 48, the tissues are collected with the forceps cups 702 abutting against the tumor 100 from the side. Therefore, invasion area of malignant lesion may not be diagnosed accurately.
In Japanese Utility Model Publication SHO 52-33146 or Japanese Patent Publication SHO 53-10396, a biopsy forceps having a mechanism to bend the flexible sheath at the distal end portion thereof is described. However, if the sheath is very thin, such a mechanism cannot be practically employed in view of the strength and operability.
A further typical treatment tool for an endoscope is a high-frequency cutting tool used for cutting human tissues using a high-frequency.
FIG. 52 shows a structure of a conventional high-frequency cutting tool for an endoscope. As shown in FIG. 52, the conventional high-frequency cutting tool includes a flexible tube 801 made of electrically insulating material. Inside the flexible tube 801, a conductive wire 802 is loosely inserted. At the distal end portion of the flexible tube 801, a pair of holes 803 are formed, which are spaced along the axial direction by a predetermined amount. Between the holes 803, the conductive wire 802 is located outside the flexible tube 801 and extends along the axis of the flexible tube 801. Further, the flexible tube 801 is provided with a plurality of circumferential grooves 804 at a predetermined interval so that the flexible tube 1 is easily bent. Such a structure is disclosed in Japanese Patent Publication SHO 64-4335.
By pulling the conductive wire as indicated by arrow in FIG. 52, the distal end portion of the flexible tube 1 between the pair of holes 803 is bent as indicated by two-dotted lines in FIG. 52.
FIG. 51 shows a usage of the high-frequency cutting tool described above. The distal end portion of the flexible tube 1 is inserted in an opening of bile duct 102 communicating with the duodenum 101, and the high-frequency current is applied to the conductive wire 802. Then, the tissues at the opening are cut. In FIG. 51, 850 denotes the endoscope and 851 denotes the treatment tool channel of the endoscope 850.
In the conventional high-frequency cutting tool as described above, the bending amount of the distal end portion of the flexible tube 801 is determined only by the pulling force of the conductive wire 802, and in accordance with the bending amount, the cutting depth 800A of the tissues is determined.
However, the bending amount cannot be controlled accurately, and therefore, the cutting depth 800A may not be different from the intended amount.